Conventionally, an image reading device for reading an image on an original has been known, including an illumination portion for irradiating light onto an original, a mirror for reflecting light from the original and forming a light path, an imaging lens for forming an image from a luminous flux from the original, and a CCD (charge-coupled device) for reading an image of the original formed by the imaging lens.
A light emitting device such as an LED (light-emitting diode) has been recently used, in addition to light emitting members such as a fluorescent lamp and a xenon tube, as a luminescence portion constituting the illumination portion. For example, an image reading device is suggested in which an illumination portion is configured by arranging a plurality of light emitting devices in a main scanning direction (Japanese Unexamined Patent Application Publication No. 2002-314760).
In addition, an image reading device is proposed that includes a light guiding body which guides light from a luminescence portion to a side of an original in order to efficiently utilize the light from the luminescence portion (see Japanese Unexamined Patent Application Publication No. 2008-35036).